18979949 has 6 divisors (see below), whose sum is σ = 19658730. Its totient is φ = 18302816.

The previous prime is 18979937. The next prime is 18979951. The reversal of 18979949 is 94997981.

It can be written as a sum of positive squares in 3 ways, for example, as 10465225 + 8514724 = 3235^2 + 2918^2 .

It is a de Polignac number, because none of the positive numbers 2^k-18979949 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 18979894 and 18979903.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18979999) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23057 + ... + 23865.

It is an arithmetic number, because the mean of its divisors is an integer number (3276455).

Almost surely, 2^18979949 is an apocalyptic number.

It is an amenable number.

18979949 is a deficient number, since it is larger than the sum of its proper divisors (678781).

18979949 is an frugal number, since it uses more digits than its factorization.

18979949 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1647 (or 838 counting only the distinct ones).

The product of its digits is 1469664, while the sum is 56.

The square root of 18979949 is about 4356.5983289718. The cubic root of 18979949 is about 266.7462649533.

The spelling of 18979949 in words is "eighteen million, nine hundred seventy-nine thousand, nine hundred forty-nine".